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Journal of Biomedicine and Biotechnology
Volume 2012 (2012), Article ID 506153, 8 pages
Research Article

PHA Productivity and Yield of Ralstonia eutropha When Intermittently or Continuously Fed a Mixture of Short Chain Fatty Acids

1Department of Agricultural and Biosystems Engineering, SAE 225/Box 2120, South Dakota State University, Brookings, SD 57006, USA
2Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57006, USA

Received 4 June 2012; Revised 1 August 2012; Accepted 2 August 2012

Academic Editor: Anuj K. Chandel

Copyright © 2012 Panchali Chakraborty et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The research described in this present study was part of a larger effort focused on developing a dual substrate, dual fermentation process to produce Polyhydroxyalkanoate (PHA). The focus of this study was developing and optimizing a strategy for feeding a mixture of SCFAs (simulated ARF) and maximizing PHA production in a cost-effective way. Three different feeding strategies were examined in this study. The substrate evaluated in this study for the growth phase of R. eutropha was condensed corn solubles, a low-value byproduct of the dry-mill, corn ethanol industry. The culture was grown to high cell densities in nitrogen-supplemented condensed corn solubles media in 5 L bioreactors. The overall growth rate of R. eutropha was 0.2 h−1. The 20 mL ARF feeding every 3 h from 48 to 109 h strategy gave the best results in terms of PHA production. PHA productivity (0.0697 g L−1 h−1), PHA concentration (8.37 g L−1), and PHA content (39.52%) were the highest when ARF was fed every 3 h for 61 h. This study proved that condensed corn solubles can be potentially used as a growth medium to boost PHA production by R. eutropha thus reducing the overall cost of biopolymer production.